The invention relates to a test set for a photometric measuring device, consisting of a mixing container which receives a first fluid in its interior and a closing element which is removable from its filling opening, and a dosing container which contains a second fluid in a sealed hollow chamber, with the dosing container being insertable in a sealing manner into the filling opening of the mixing container, with the second fluid being conveyed into the interior of the mixing container by pressing a sealing plunger of the dosing container and being mixed with the same. The invention further relates to a photometric measuring method for a sample fluid which is mixed with a first and second fluid.
In many medical tests, the sample to be measured needs to be brought into contact at first with a first fluid in order to condition the sample, prepare the same for the measurement or initiate a first chemical or biological reaction. In a second step, the second fluid is added in order to transfer the analyte of the sample to be determined to a state suitable for photometric measurement or to initiate a second chemical or biological reaction. For example, in a so-called CRP measurement (C-reactive protein) which is used for distinguishing viral or bacterial inflammations, a blood sample is mixed with a lysis reagent and thereafter a latex reagent is added and mixed, with the chemical reaction being measured with the help of a photometer.
A test set of the kind mentioned above is known for example from WO 2007/053870 A2. The test set comprises a mixing container and a dosing container that can be inserted into the mixing container. The mixing container is equipped with a closing element which can be removed from a filling opening and contains a first fluid, with the dosing container being insertable into the filling opening of the mixing container after the removal of the closing element and the addition of the sample fluid to the first fluid. The dosing container contains a second fluid in a sealed hollow chamber, with the hollow chamber being sealed on the one side by a sealing plunger on the one side and by a movable plug on the other side, which after pressurizing the sealing plunger conveys the second fluid together with the movable plug into the interior of the mixing container. After the mixture of the sample with the first fluid and the second fluid, the mixing container is used in a photometric analyzer, whereupon the sample ingredients are photometrically measured. The known methods are susceptible to errors because precise sample quantities need to be supplied which are precisely required for the respective test set and the respective medical test.
A sample-taking and measuring element is known from WO 2005/071388 A1 which consists of several cylindrical compartments which are inserted into each other in an axially displaceable way, with their inside spaces being sealed in the initial position by a penetrable membrane. Two of the elements contain reagents and a sample can be introduced into the third element by a swab. The compartments are slid into each other by exerting pressure on the two outer elements, as a result of which the membranes tear at the connecting points and simultaneously the two reagent fluids are mixed with the sample. Analysis occurs either by optical inspection or by using a measuring device.
DE 24 41 724 A1 describes an analytic cartridge for photospectrometric measurements, comprising a first container for receiving a first fluid, with the container being sealed at first by a closing element. After the removal of the closing element, the sample to be analyzed is placed in the container and a container insert is then placed on the same which comprises a reagent fluid in an auxiliary chamber. The auxiliary chamber is provided with a cylindrical tappet which in the initial position protrudes beyond the container insert and which, when pressed down, tears open a membrane of the auxiliary chamber with the help of a cutting edge on the front side and thus releases the second fluid from the auxiliary chamber into the container with the first fluid. Once the fluids have dissolved and are mixed completely, the container is heated in the manner required for the analytic method and the sample is measured in a photometric way.
It is the object of the invention to provide a photometric measuring method for a sample fluid which offers simplest possible handling, with a improved test set being used with which errors in the precise sample dosing is to be substantially prevented. In particular, precise dosing of the sample fluid shall be enabled.